I mistakenly purchased AC-AC SSR’s from Amazon, which explains why they don’t function. I have this one from my previous Arduino build. Think I could use this one?
Yes, that looks like it will work.
Yes, but if you are using PWM an SSR would be better because you’ll be switching frequently. They also have the benefit of switching on a zero crossing, so you will have less of an inrush current and less EMI.